Lightweight Child-Resistant Closure

ABSTRACT

A child-resistant container closure includes a base cap having a plurality of upwardly extending teeth and one or more ramps protruding radially outwardly from a skirt, and a cover cap having a plurality of downwardly extending teeth adapted for engagement with the teeth of the base cap and one or more ramps protruding radially inwardly from a skirt, the cover cap ramps being adapted for engagement with the base cap ramps, and springs urging the cover cap apart from the base cap for enabling selective engagement between the base cap teeth and the cover cap teeth.

RELATED APPLICATION

This application is claims priority from U.S. Provisional Application No. 61/200,148, filed Nov. 25, 2008, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The application relates to a lightweight container closure or cap, and in particular to a container closure having a child-resistant safety feature to inhibit opening of the container by a child.

BACKGROUND

Child-resistant container closures are known in the art. Such closures typically have a nested two-cap construction, including a base cap for sealing a container opening and a cover cap that captures the base cap. The base cap threads onto a neck of the container about the opening. Cooperating features disposed on an inner portion of the cover cap and an outer portion of the base cap enable selective engagement between the base cap and the cover cap, such that a single rotational action is sufficient to install the closure onto the container while a combined rotational and pushing and/or squeezing action is required to remove the closure from the container. In practice, when the cover cap is rotated in a first direction so as to thread the base cap onto the container neck, the cover cap and the base cap reliably engage and rotate in tandem, but when the cover cap is rotated in second a direction so as to unthread the base cap from the container neck, the cover cap must be further manipulated (e.g., by pushing downward on the cover cap or squeezing a portion of the cover cap while rotating) to cause the base cap to rotate in tandem with the cover cap. If the cover cap is rotated in the second direction without further manipulating the cover cap, the closure may emit a clicking sound to indicate a failed attempt to open the closure. However, in many existing closures, the clicking sound is only faintly audible.

SUMMARY

In one embodiment, a child-resistant container closure includes a base cap, a cover cap, and one or more springs or resilient members. The base cap has a top and a skirt depending downwardly from the top, the base cap including a plurality of upwardly extending teeth, the skirt including internal threads for engaging a neck of the container, a bottom end, and one or more ramps protruding radially outwardly from the skirt. The cover cap has a top and a skirt depending downwardly from the top, the cover cap including a plurality of downwardly extending teeth adapted for engagement with the upwardly extending teeth of the base cap top. The skirt has a plurality of interspersed vertical legs each spaced apart from adjacent legs by vertical openings, the legs being joined by a support ring, the skirt including one or more ramps protruding radially inwardly from the legs. The ramps are adapted for asymmetric engagement with the outwardly protruding ramps of the base cap skirt. The springs enable selective engagement between the base cap upwardly extending teeth and the cover cap downwardly extending teeth. In a rest or non-engaged state the springs cause the base cap top and the cover cap top to be separated by an at-rest distance such that the cover cap is rotatable separately from the base cap without the respective teeth engaging (i.e., the teeth are not engaged). In an actuated state in which the cover cap is displaced toward the base cap, the springs deflect so as to allow the distance between the cover cap top and the base cap top to decrease to an actuated distance to enable the respective teeth to engage such that the rotation of the cover cap causes the base cap to rotate along with the cover cap. In the rest state, when the cover cap is rotated in a first direction, the cover cap ramps positively engage the base cap ramps to cause the base cap to rotate along with the cover cap in the first direction. In the rest state, when the cover cap is rotated in a second direction, the cover cap ramps slide over the base cap ramps causing an audible clicking sound as a closing face of each of the cover cap ramps releases from a closing face of each of the corresponding base cap ramps.

In another embodiment, a child-resistant container closure includes a base cap, a cover cap, and a plurality of springs. The base cap has a top and a skirt depending downwardly from the top, the base cap including a plurality of upwardly extending teeth, the skirt including internal threads for engaging a neck of the container, a bottom end, and one or more ramps protruding radially outwardly from the skirt. The cover cap has a top and a skirt depending downwardly from the top, the cover cap including a plurality of downwardly extending teeth adapted for engagement with the upwardly extending teeth of the base cap top, the skirt having a support ring at a bottom end thereof. The skirt includes one or more ramps protruding radially inwardly from the legs, the ramps being adapted for asymmetric engagement with the outwardly protruding ramps of the base cap skirt. The support ring protrudes radially inwardly from the cover cap skirt to engage with a ridge protruding radially outwardly from the bottom end of the base cap skirt to inhibit removal of the cover cap from the base cap. The springs are spaced apart and are arranged in a generally circular pattern protruding downwardly from the top of the cover cap and an annular ridge protrudes upwardly from the top of the base cap, the ridge engaging the springs for centering the cover cap on the base cap, the ridge having a shaped surface for guiding the flexure of the springs for enabling selective engagement between the base cap upwardly extending teeth and the cover cap downwardly extending teeth. In a rest state, the springs cause the base cap top and the cover cap top to be separated by an at-rest distance such that the cover cap is rotatable separately from the base cap without the respective teeth engaging. In an actuated state in which the cover cap is displaced toward the base cap, the springs deflect so as to allow the distance between the cover cap top and the base cap top to decrease to an actuated distance to enable the respective teeth to engage such that the rotation of the cover cap causes the base cap to rotate along with the cover cap. In the rest state, when the cover cap is rotated in a first direction, the cover cap ramps positively engage the base cap ramps to cause the base cap to rotate along with the cover cap in the first direction. In the rest state, when the cover cap is rotated in a second direction, the cover cap ramps slide over the base cap ramps causing an audible clicking sound as a closing face of each of the cover cap ramps releases from a closing face of each of the corresponding base cap ramps.

Other objects, aspects and advantages of the present invention will become apparent to those skilled in the art upon reading the following detailed description, when considered in conjunction with the appended claims and the accompanying drawings briefly described below.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein:

FIG. 1 is a top perspective view of a closure showing a base cap captured within a cover cap.

FIG. 2 is a bottom perspective view of the cover cap of FIG. 1.

FIG. 3 is a bottom plan view of the cover cap of FIG. 2.

FIG. 4 is a top perspective view of the base cap of FIG. 1.

FIG. 5 is a top plan view of the base cap of FIG. 4.

FIG. 6 is a side cross-sectional view of the closure of FIG. 1.

DETAILED DESCRIPTION

Referring to FIGS. 1 and 6, an embodiment of a child-resistant container closure 10 is depicted. The closure 10 is a two-piece device including a cover cap 100 and a base cap 200. The base cap 200 is designed to seal a container opening by threading onto a neck of the container. The cover cap 100 is designed to snap around and capture the base cap 200, as depicted in FIGS. 1 and 6, and as is described in detail below.

With particular reference to FIGS. 2 and 3, the cover cap 100 includes a top 110 and a skirt 120 depending downwardly from a periphery of the top 110. The skirt 120 extends from a top end adjoining the top 110 to a bottom end 126. The skirt 120 has a plurality of interspersed vertical legs 122 and vertical cut-outs or openings 124. The legs 122 and the openings 124 alternate preferably in a regular pattern and the legs 122 are joined together at a bottom end 126 of the skirt 120 by a support ring 128. The support ring 128 provides rigidity to the skirt 120 while the openings 124 enable the skirt 120 to be lighter in weight and to use less material than a conventional solid skirt. Among other benefits, the interspersed legs 122 and slots 124 provide a good gripping surface for a user, particularly for a user with arthritis, advanced age, or other condition that limits gripping strength.

With particular reference to FIGS. 4 and 5, the base cap 200 includes a top 210 and a skirt 220 depending downwardly from a periphery of the top 210. The skirt 220 extends from a top end adjoining the top 210 to a bottom end 224. Internal threads 222 protrude inwardly from the skirt 220 for engagement with a container neck. The base cap 200 has an outer diameter and the cover cap 100 has an inner diameter, the outer diameter of the base cap 200 being sufficiently smaller than the inner diameter of the cover cap 100 to create an annular gap 300, as shown in FIG. 6. Accordingly, if there were no outward protrusions from the base cap skirt 220 and no inward protrusion from the cover cap skirt 120, the gap 300 would permit the cover cap 100 to rotate freely about the base cap 200 without interference or contact with the base cap 200.

To prevent the cover cap top 110 from resting in direct contact with the base cap top 210, one or more springs or resilient members 150 are provided to maintain the top 110 of the cover cap 100 spaced apart from the top 210 of the base cap 200 by a distance 310 between the cover cap top 110 and the base cap top 210. In a rest or non-engaged state, when the cover cap 100 is not actuated or depressed toward the base cap 200, the springs 150 establish an at-rest distance. In an actuated or engaged state, when a user applies downward force to displace the cover cap 100 toward the base cap 200, the springs 150 establish an actuated distance that is less than the at-rest distance. When the downward force is removed, the springs 150 cause the cover cap 100 to move away from the base cap 200 thus restoring the distance from the actuated distance to the at-rest distance.

In the depicted embodiment, the springs 150 comprise a plurality of individual spring members 152 extending downwardly from the cover cap top 110. The spring members 152 are spaced apart in a substantially circular or circumferential pattern and have a length approximately equal to or greater than the at-rest distance to be maintained between the cover cap top 110 and the base cap top 210. A raised annular ridge 214 protrudes upwardly from the base cap top 210. As shown, the diameter of the annular ridge 214 is slightly less than the diameter of the circular pattern formed by tips 158 of the springs 150, so that the interaction between the springs 150 and the ridge 214, as discussed below, causes the cover cap 100 to be in a substantially centered disposition with respect to the base cap 200. However, it is understood that the cover cap 100 could be similarly centered on the base cap 200 if the annular ridge 214 were to have a diameter slightly larger than the diameter of the circular pattern of the springs 150. It is also contemplated that, instead of a ridge, a channel could be formed on the base cap to provide centering for the springs 150.

The annular ridge 124 has a shaped surface 216 for guiding the flexure of the springs 150 as the closure 10 moves from the rest state to the actuated state. In particular, the shaped surface 216 preferably has a concave curvature where the ridge 214 joins the top 210 to direct the flexing of the spring members 152 as the distance between the top 110 and the top 210 becomes smaller relative to the length of the spring members 152.

In one embodiment, as most clearly shown in FIGS. 2, 3, and 6, a groove 154 is provided on one or both sides of each spring member 152 to enhance the ability of the spring member 152 to flex at the junction of the spring member 152 and the top 110 without fracturing. The groove 154 results in a longer length of spring member 152, thus increasing the flexibility of the spring member 152. The spring members 152 can also be tapered from thicker at a base where the spring members 152 attach to the top 110 to thinner at a tip. As shown in FIG. 6, the tip preferably is curved, sloped, or chamfered on one side to facilitate the initial bending of the spring member 152 in one direction.

It is understood that the springs may alternatively comprise a plurality of individual spring members 152 extending upwardly from the base cap top 210 cooperating with an annular ridge 214 protruding downwardly from of a channel disposed in the cover cap top 110.

As shown in FIGS. 2, 3, and 6, a plurality of teeth 130 extend downwardly preferably from the top 110 of the cover cap 100. The teeth 130 are circumferentially spaced apart at a regular spacing distance. As shown in FIGS. 4, 5, and 6, a plurality of teeth 230 extend upwardly preferably from the top 210 of the base cap 200. The teeth 230 are circumferentially spaced apart at a regular distance. The positions of the teeth 230 of the base cap 200 substantially correspond to the positions of the teeth 130 of the cover cap 100 to enable engagement or meshing between the teeth 130, 230. The number of teeth 130 and the number of teeth 230 need not be the same, but are preferably multiples of each other. As shown in one embodiment, there are twelve teeth 130 and twelve teeth 230, so that when the teeth are able to engage, the cover cap 100 can have a free play of no more than about 30 degrees (or one-twelfth of a rotation) before engaging the base cap 200. Note that even if only one of the sets of teeth has twelve teeth and the other set of teeth has an even fraction of twelve teeth (e.g., two, three, four, or six teeth), the same amount of free play would be achieved, but the engagement force would be spread across less pairs of meshing teeth 130, 230. Accordingly, the number of teeth 130 and the number of teeth 230 can be selected to achieve the desired amount of free play between the cover cap 100 and the base cap 200 and the required engagement force between the sets of teeth 130, 230.

As shown in FIGS. 4 and 5, the teeth 230 may be shaped with an asymmetric bias (i.e., ramped), rising nearly perpendicularly from the base cap top 210 at an engagement face 232 and having legs 234, 236 that taper to the base cap top 210 opposite the engagement face 232. The asymmetry of the teeth 230 enables the teeth 230 to engage the teeth 130 with a greater force in one direction of rotation than in the opposite direction of rotation. In particular, because the primary function of the teeth 130, 230 is to enable removal of the closure 10 from the container but not necessarily to enable installation of the closure 10 onto the container, the tooth 130 engages with the tapered legs 234, 236 of the tooth 130 when the cover cap 100 is rotated in a first, installation or tightening, direction (typically clockwise for right-handed threads 222) and with the engagement face 232 of the tooth 130 when the cover cap 100 is rotated in a second, removal or loosening, direction (typically counter-clockwise for right-handed threads 222). The asymmetric bias of the teeth 130 enables the teeth 130, 230 to interact with sufficient force to open the closure 10 when the cover cap 100 is rotated in the second direction but prevents accidental over-tightening of the closure 10 onto the container when the cover cap 100 is rotated in the first direction. One benefit of forming the teeth on the base as shown is that less material is used while still providing a structural engagement surface.

The teeth 130 and the teeth 230 have a combined height that is at least slightly less than the at-rest distance between the top 110 and the top 210, such that when the cover cap 100 is not actuated toward the base cap 200, the teeth 130, 230 cannot engage with one another, and the cover cap 100 can be rotated freely, at least in the second direction, without rotating the base cap 200.

As best illustrated in FIGS. 2, 3, and 6, the cover cap 100 further includes one or more cover cap ramps 140 protruding radially inwardly from the skirt 120, and more specifically from a corresponding one or more legs 122 of the skirt 120. The ramp 140 has a gently sloped opening or ramped face 142 and a more sharply sloped closing or engagement face 144. In the depicted embodiment, the opening face 142 slopes at an angle of about 20 degrees with respect to the circumferential shape of the skirt 120. An effective ramp 140 can include a opening face 142 sloping in the range of about 5 degrees to about 45 degrees. An opening face slope of less than about 5 degrees will likely cause the ramp 140 to be excessively long and an opening face slope of greater than about 45 degrees will likely cause the rise to be too sharp for the closure 10 to operate as desired. The closing face 144 can be disposed substantially perpendicularly to the skirt 120 or more preferably can slope in either direction with respect to perpendicular. If the closing face 144 slopes in the opposite direction to the opening face 142, the slope should be limited to no more than about 10 degrees from perpendicular to achieve the desired operation of the closure 10. As depicted, the closing face preferably slopes in the same direction as the opening face 142. The slope of the closing face 144 in this direction should be limited to no more than about 20 degrees from perpendicular to the skirt 120 to maintain the required structural rigidity of the ramp 140 near its apex 146 where the faces 142, 144 join. By sloping the closing face 144 in the same direction as the opening face 142, the ramp 140 can interlock with a corresponding ramp 240 on the base cap 200. This functions to draw the teeth together, thereby preventing the legs 22 from flexing away from the base cap 200 when rotational torque is applied to the cover cap 100. Further, by maintaining a sharp and rigid apex 146, the audible clicking sound created by the release of the ramps 140 from corresponding ramps 240 on the base cap 200 can be enhanced, as explained below.

As best illustrated in FIGS. 4, 5, and 6, the base cap 200 further includes one or more base cap ramps 240 protruding radially outwardly from the skirt 220. The ramp 240 has a gently sloped opening or ramped face 242 and a more sharply sloped closing or engagement face 124. In the depicted embodiment, the opening face 242 slopes at an angle of about 20 degrees with respect to the circumferential shape of the skirt 220. An effective ramp 240 can include an opening face 242 sloping in the range of about 5 degrees to about 45 degrees. The closing face 244 can be disposed substantially perpendicularly to the skirt 220 or can slope in either direction with respect to perpendicular. If the closing face 244 slopes in the opposite direction to the opening face 242, the slope should be limited to no more than about 10 degrees from perpendicular to achieve the desired operation of the closure 10. As depicted, the closing face slopes in the same direction as the opening face 242. The slope of the closing face 244 in this direction should be limited to no more than about 20 degrees from perpendicular to the skirt 220 to maintain the required structural rigidity of the ramp 240 near its apex 246 where the faces 242, 244 join. By sloping the closing face 244 in the same direction as the opening face 242, the ramp 240 can interlock with a corresponding ramp 140 on the cover cap 100 to prevent the legs 22 from flexing away from the base cap 200 when rotational torque is applied to the cover cap 100, as discussed above. Further, by maintaining a sharp and rigid apex 246, the audible clicking sound created by the release of the ramps 240 from corresponding ramps 140 on the cover cap 100 can be enhanced, as explained below.

The combined distance by which the ramps 140 protrude inwardly from the cover cap skirt 120 and the ramps 240 protrude outwardly from the base cap skirt 220 is at least large enough to slightly exceed the annular gap 300 between the skirt 120 and the skirt 220. Therefore, as the cover cap 100 is rotated in either direction with respect to the base cap 200, the respective ramps 140, 240 necessarily interact.

When the cover cap 100 is rotated in the first or tightening direction of rotation, the sharp closing face 244 of the ramp 240 comes into contact with the sharp closing face 144 of the ramp 140 and the ramps 140, 240 engage with each other in a manner that strongly inhibits, but does not completely prevent, further rotation of the cover cap 100 with respect to the base cap 200.

Therefore, as long as the threads 222 of the base cap 100 are not fully and tightly engaged with corresponding threads on the container neck, further rotation of the cover cap 100 in the first direction will cause the base cap 200 to rotate along with the cover cap 100 in the first direction. Once the threads 222 of the base cap 100 become fully engaged with the corresponding threads on the container neck, the ramps 140, 240 remain engaged to tighten the threaded engagement to secure the closure 10 on the container sufficiently to prevent accidental or inadvertent loosening of the closure 10. It is well within the knowledge of a typical user of container closures 10 to estimate the amount of tightening that is sufficient. If a user attempts to significantly over-tighten the closure 10 onto the container, the legs 122 of the cover cap skirt 120 eventually flex enough to permit the closing faces 144 of the ramps 140 to disengage from the closing faces 244 of the ramps 240 so that the cover cap 100 jumps or rotates with respect to the based cap 200 until the next ramp-to-ramp (140-to-240) engagement, indicating to the user that the closure 10 is at least sufficiently tight.

When the cover cap 100 is not depressed such that the springs 150 are in the rest state, and the cover cap 100 is rotated in the first direction, the interaction between the ramps 140, 240 is the only mechanism that enables tightening of the base cap 200 onto the container. When the spring means 150 is in the actuated state and the cover cap 100 is rotated in the first direction, the interaction between the ramps 140, 240 may be supplemented by the interaction between the teeth 130, 230; as described above, the engagement between teeth 130, 230 in the first direction is also preferably designed to automatically limit the amount of tightening force that can be applied to tighten the closure 10 onto the container 10, as a result of the tapered legs 234, 236.

When the cover cap 100 is rotated in the second or loosening direction of rotation, the shallow opening face 242 of the ramp 240 comes into contact with the shallow opening face 142 of the ramp 140 and the ramps 140, 240 engages with each other in a manner that provides a gentle and minimal frictional force between the ramps 140, 240, as the opening faces 142, 242 slidably engage with, and slide over, each other. The frictional interaction between the opening faces 142, 242 is insufficient to overcome the holding force of a sufficiently tightened base cap 200. In other words, when the base cap 200 is fully and sufficiently tightened onto the container, the frictional interaction between the opening faces 142, 242 is not enough to loosen the base cap 200. Therefore, when the threads 222 of the base cap 100 are fully engaged with the corresponding threads on the container neck, the legs 122 of the cover cap skirt 120 flex enough to permit the opening faces 142 of the ramps 140 to slide completely over and release from the opening faces 242 of the ramps 240.

When the release occurs, and the apex 146 releases from the apex 246, an audible clicking sound is emitted, and the cover cap 100 jumps or rotates with respect to the base cap 200 until the next ramp-to-ramp (140-to-240) engagement, during which the opening faces 142 of the ramps 140 again slide completely over and release from the opening faces 242 of the ramps 240, making the clicking sound again, the process repeating as long as a user continues to rotate the cover cap 100 in the second direction and the springs 150 are in the rest state. The audible clicking sound serves two purposes. First, it reminds a user that the closure 10 is a child-resistant cap and that a more complex pushing and rotating action is required to open the closure 10. Second, it provides an audible alert to an adult in the event a child is attempting to open the closure 10. A particular advantage of the closure 10 is that the openings 124 in the skirt 120 permit the clicking sound made by the releasing of the ramps 140, 240 from each other to more readily escape from within the cover cap 100, thereby making the sound louder and more audible by a user or an adult responsible for the safety of a child. Testing has shown an appreciable increase in the audible sound caused by the openings 124 in the skirt 120.

As described, when the cover cap 100 is not depressed such that the springs 150 are in the rest state, the base cap 200 is tightened on the container neck, and the cover cap 100 is rotated in the second direction, the interaction between the ramps 140, 240 serves only to create an audible sound. Therefore, to open the closure 10, the springs 150 must be actuated to the actuated state by depressing the cover cap 100 toward the base cap 200, to cause engagement of the teeth 130, 230. When the cover cap 100 is depressed such that the springs 150 are in the actuated state, and the cover cap 100 is rotated in the second direction, the teeth 130, 230 engage and mesh as described above. In particular, the engagement between the teeth 130 and the engagement faces 232 of the teeth 230 provides sufficient engagement force to overcome the tightening of the base cap threads 222 onto the container neck threads so that the closure 10 can be loosened from the container neck.

In the illustrated embodiment, the base cap skirt 220 includes six ramps 240 and the cover cap skirt 120 includes three ramps 140. It is understood that the number of cover cap ramps 140 and the number of base cap ramps 240 need not be the same, and that the number of ramps 140, 240 can be selected to achieve a combination of a desired engagement force in the first direction of rotation, a desired engagement force in the second direction of rotation, and a level of audible clicking sound. For example, for a relatively small closure 10, the combination of four cover cap ramps 140 and one base cap ramp 240 may be adequate to enable sufficient tightening of the closure 10 and to prevent unintended opening of the closure 10. However, for a larger closure 10, it may be necessary to have eight or more cover cap ramps 140 in combination with four or more base cap ramps 240 to provide sufficient tightening force while still not provide excessive loosening force.

The cover cap 100 and the base cap 200 are held together to form the closure 10, such that the cover cap 100 is rotatable with respect to the base cap 200 but the cover cap 100 is not readily removable from the base cap 200. Capturing the base cap 200 within the cover cap 100 in this manner prevents a child from circumventing the safety features of the closure 10 by simply removing the cover cap 100 to directly rotate the base cap 200. In the embodiment of the closure 10 as shown particularly in FIGS. 1 and 6, the cover cap support ring 128 protrudes radially inwardly from the bottom end 126 of the skirt 120 to bridge the gap 300, such that when the cover cap 100 is installed over the base cap 200, a rim of the support ring 128 is beneath the bottom end 224 of the base cap skirt 220. Therefore, if a user or a child attempts to lift the cover cap 100 off of the base cap 200, the rim will contact the bottom end 224 of the base cap skirt 220 and prevent removal of the cover cap 100. It is understood, however, that the cover cap skirt 120 and the support ring 128, as well as the base cap skirt 220, are sufficiently flexible that if a large enough force and/or a skewed force is applied when attempting to lift the cover cap 100, the cover cap 100 can be forcibly removed from the base cap 200. To further inhibit the removal of the cover cap 100 from the base cap 200, the bottom end 224 of the base cap skirt 200 can also include a ridge 226 protruding outwardly therefrom for engagement with the support ring 128.

As a further safety feature, the openings 124 in the cover cap skirt 120 may be sized to be sufficiently small so as to prevent a child's fingers from directly accessing and turning the base cap 200 without having to rely on the engagement between the cover cap 100 and the base cap 200 to open the closure 10.

Although specific embodiments have been described, the skilled artisan will understand how various modifications may be made within the scope of the present invention, which is defined by the attached claims. 

1. A child-resistant container closure comprising: a base cap having a top and a skirt depending downwardly from the top, the base cap including a plurality of upwardly extending teeth, the skirt including internal threads for engaging a neck of the container, a bottom end, and one or more ramps protruding radially outwardly from the skirt; a cover cap having a top and a skirt depending downwardly from the top, the cover cap including a plurality of downwardly extending teeth adapted for engagement with the upwardly extending teeth of the base cap, the skirt having a plurality of interspersed vertical legs each spaced apart from adjacent legs by vertical openings, the legs being joined by a support ring, the skirt including one or more ramps protruding radially inwardly from the legs, the ramps being adapted for asymmetric engagement with the outwardly protruding ramps of the base cap skirt; and one or more springs for enabling selective engagement between the upwardly extending teeth of the base cap and the downwardly extending teeth of the cover cap; wherein in a rest state the springs cause the base cap top and the cover cap top to be separated by an at-rest distance such that the cover cap is rotatable separately from the base cap without the respective teeth engaging; wherein in an actuated state in which the cover cap is displaced toward the base cap, the springs deflect to allow the distance between the cover cap top and the base cap top to decrease to an actuated distance to enable the respective teeth to engage such that the rotation of the cover cap causes the base cap to rotate along with the cover cap; wherein, in the rest state, when the cover cap is rotated in a first direction, the cover cap ramps positively engage the base cap ramps to cause the base cap to rotate along with the cover cap in the first direction; and wherein, in the rest state, when the cover cap is rotated in a second direction, the cover cap ramps slide over the base cap ramps causing an audible clicking sound as a closing face of each of the cover cap ramps releases from a closing face of each of the corresponding base cap ramps.
 2. The closure of claim 1, the springs protrude downwardly from the top of the cover cap.
 3. The closure of claim 1, the springs comprising a plurality of spaced apart spring members arranged in a generally circular pattern protruding downwardly from the top of the cover cap.
 4. The closure of claim 3, further comprising an annular ridge protruding upwardly from the top of the base cap, the ridge engaging the spring members for centering the cover cap on the base cap, the ridge having a shaped surface for guiding the flexure of the springs in the actuated state.
 5. The closure of claim 3, wherein a base end of each of the spring members is recessed into the cover cap top to provide a spring length that is greater than the at-rest distance between the top of the cover cap and the top of the base cap.
 6. The closure of claim 3, wherein the spring members are at least partially tapered so as to be thicker at a base to thinner at a tip.
 7. The closure of claim 7, wherein the tip of the spring members is tapered on one side to facilitate initial bending of the spring member.
 8. The closure of claim 1, the springs comprising: a plurality of spaced apart spring members arranged in a generally circular pattern protruding upwardly from the top of the base cap.
 9. The closure of claim 8, further comprising an annular ridge protruding downwardly from the top of the cover cap, the ridge engaging the spring members for centering the cover cap on the base cap, the ridge having a shaped surface for guiding the flexure of the springs in the actuated state.
 10. The closure of claim 1, each of the base cap ramps having an opening face opposite the closing face, the opening face and the closing face slanting in the same direction with respect to a base cap radius; and each of the cover cap ramps having an opening face opposite the closing face, the opening face and the closing face slanting in the same direction with respect to a cover cap radius; wherein the engagement of the respective slanted closing faces provides a positive engagement between the respective ramps for turning the base cap when the cover cap is rotated in the first direction; and wherein the engagement of the respective slanted opening faces enables the ramps to slide over one another, the slanted closing faces enhancing the audibility of the sound emitted as the sliding engagement releases.
 11. The closure of claim 1, the vertical legs in the cover cap skirt have flexibility to allow the cover cap ramps and the base cap ramps to slidably engage and release from one another when the cover cap is rotated in the second direction but have rigidity to enable the respective ramps to positively engage the base cap ramps to cause the base cap to rotate along with the cover cap in the first direction.
 12. The closure o f claim 1, the vertical openings in the cover cap being small enough to prevent a child's fingers from accessing and turning the base cap independently from the cover cap, and being configured to permit the audible clicking sound to emit from the closure.
 13. The closure o f claim 1, the support ring of the cover cap including a rim which engages with the bottom face of the base cap to inhibit removal of the cover cap from the base cap.
 14. The closure o f claim 1, wherein one or the other of the cover cap teeth and the base cap teeth is shaped to provide for greater engagement force in the first direction than in the second direction when the closure is in the actuated state.
 15. A child-resistant container closure comprising: a base cap having a top and a skirt depending downwardly from the top, the base cap including a plurality of upwardly extending teeth, the skirt including internal threads for engaging a neck of the container, a bottom end, and one or more ramps protruding radially outwardly from the skirt; a cover cap having a top and a skirt depending downwardly from the top, the cover cap including a plurality of downwardly extending teeth adapted for engagement with the upwardly extending teeth of the base cap top, the skirt including one or more ramps protruding radially inwardly from the legs, the ramps being adapted for asymmetric engagement with the outwardly protruding ramps of the base cap skirt, the skirt having a support ring protruding radially inwardly from the cover cap skirt to engage with a ridge protruding radially outwardly from the bottom end of the base cap skirt to inhibit removal of the cover cap from the base cap; and a plurality of spaced apart springs arranged in a generally circular pattern protruding downwardly from the top of the cover cap and an annular ridge protruding upwardly from the top of the base cap, the ridge engaging the springs for centering the cover cap on the base cap, the ridge having a shaped surface for guiding the flexure of the springs for enabling selective engagement between the upwardly extending teeth of the base cap and the downwardly extending teeth of the cover cap; wherein in a rest state the springs cause the base cap top and the cover cap top to be separated by an at-rest distance such that the cover cap is rotatable separately from the base cap without the respective teeth engaging; wherein in an actuated state in which the cover cap is displaced toward the base cap, the spring deflect to allow the distance between the cover cap top and the base cap top to decrease to an actuated distance to enable the respective teeth to engage such that the rotation of the cover cap causes the base cap to rotate along with the cover cap; wherein, in the rest state, when the cover cap is rotated in a first direction, the cover cap ramps positively engage the base cap ramps to cause the base cap to rotate along with the cover cap in the first direction; and wherein, in the rest state, when the cover cap is rotated in a second direction, the cover cap ramps slide over the base cap ramps causing an audible clicking sound as a closing face of each of the cover cap ramps releases from a closing face of each of the corresponding base cap ramps.
 16. The closure of claim 15, wherein a base end of each of the spring members is recessed into the cover cap top to provide a spring length that is greater than the at-rest distance between the top of the cover cap and the top of the base cap.
 17. The closure o f claim 15, each of the base cap ramps having an opening face opposite the closing face, the opening face and the closing face slanting in the same direction with respect to a base cap radius; and each of the cover cap ramps having an opening face opposite the closing face, the opening face and the closing face slanting in the same direction with respect to a cover cap radius; wherein the engagement of the respective slanted closing faces provides a positive engagement between the respective ramps for turning the base cap when the cover cap is rotated in the first direction; and wherein the engagement of the respective slanted opening faces enables the ramps to slide over one another, the slanted closing faces enhancing the audibility of the sound emitted as the sliding engagement releases.
 18. The closure of claim 15, the cover cap skirt having a plurality of interspersed vertical legs each spaced apart from adjacent legs by vertical openings, the legs being joined by the support ring, the vertical openings in the cover cap being small enough to prevent a child's fingers from accessing and turning the base cap independently from the cover cap, and being configured to permit the audible clicking sound to emit from the closure.
 19. The closure o f claim 15, wherein one or the other of the cover cap teeth and the base cap teeth is shaped to provide for greater engagement force in the first direction than in the second direction when the closure is in the actuated state. 